I hand load for my AR , here is my load data. 55gr Hornady fmjbt, 24.5 grs of H335, cci#400 primer in once fired brass.
When I shoot the above rounds I get black around the case neck and the primers look flattened out. Is this normal ?
This load is no where near a max load, it is actually a modest load. It's a full 2 grs below max. Is there any way possible this is a sign of too much pressure ?

I already deprimed them so I will take some pics next time I shoot some rounds.
They did not seem to be loose, they seated like normal and they punched out like normal. But now tyhat you mentioned loose, I did remove the military crimp using a lyman primer pocket reamer and it goes in all the way to the bottom of the primer pocket. Sure hope I didn't ruin a bunch of cases.

My case necks also get blackened a bit with H335, but I've loaded much heavier loads than 24.5 with no signs of pressure. Even though every gun is a bit different I would think that is a pretty safe load. You should be able to tell if you have a primer pocket problem when you prime your cases, it should be a fairly snug fit and take a little pressure to get them to seat, same when you deprimed, mine usually kind of pop out, I would think if your primer pockets were to big they would kind of slide out without much pressure.

rebs - the load you are using should be really safe. Check how well the primers seat when you prime the cases, or when you deprime the fired cases pay attention to how much it takes to kick the fired primer out. I used the Lyman reamer for years and it was never a problem. Now I swage them.

When you are sizing your cases, how do you set up your die? If you aren't measuring and just adjusting the die "1/4 turn past when it makes contact with the shell holder" or something like that, you might be setting the shoulder back excessively.

If you have excess head space due to setting the shoulder back too far, it cause primers to flatten even with normal pressure loads. With some powders and lighter loads I get black on the outside of the case neck due to it not sealing tight enough in the chamber.

When you are sizing your cases, how do you set up your die? If you aren't measuring and just adjusting the die "1/4 turn past when it makes contact with the shell holder" or something like that, you might be setting the shoulder back excessively.

If you have excess head space due to setting the shoulder back too far, it cause primers to flatten even with normal pressure loads. With some powders and lighter loads I get black on the outside of the case neck due to it not sealing tight enough in the chamber.

Yes I did just adjust the die according to the directions, how do I measure the shoulder to get it correct ?

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